Current work-in-progress crbug.com/567021

third_party/WebKit/Source/core/dom/StyleElement.cpp

 /*
  * Copyright (C) 2006, 2007 Rob Buis
  * Copyright (C) 2008 Apple, Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 79 matching lines @@
 
     if (shadowRoot)
         shadowRoot->unregisterScopedHTMLStyleChild();
 
     Document& document = element->document();
     if (m_registeredAsCandidate) {
         document.styleEngine().removeStyleSheetCandidateNode(element, shadowRoot ? *toTreeScope(shadowRoot) : toTreeScope(document));
         m_registeredAsCandidate = false;
     }
 
-    StyleSheet* removedSheet = m_sheet.get();
-
-    if (m_sheet)
+    if (m_sheet) {
         clearSheet(element);
-    if (removedSheet)
-        document.styleEngine().setNeedsActiveStyleUpdate(removedSheet, AnalyzedStyleUpdate);
+        if (element->inShadowIncludingDocument())
+            document.styleEngine().setNeedsActiveStyleUpdate(element->treeScope());
+    }
 }
 
 void StyleElement::clearDocumentData(Document& document, Element* element)
 {
     if (m_sheet)
         m_sheet->clearOwnerNode();
 
     if (m_registeredAsCandidate) {
         DCHECK(element->inShadowIncludingDocument());
         document.styleEngine().removeStyleSheetCandidateNode(element, element->treeScope());
@@ skipping 111 matching lines @@
 {
     document.styleEngine().addPendingSheet(m_styleEngineContext);
 }
 
 DEFINE_TRACE(StyleElement)
 {
     visitor->trace(m_sheet);
 }
 
 } // namespace blink